1. Field
Embodiments described generally relate to the production and processing of hydrocarbons. More particularly, such embodiments relate to subsea hydrocarbon production and processing.
2. Description of the Related Art
Subsea production systems are widely used in producing oil and/or gas containing fluids, e.g., hydrocarbon production fluids, from deepwater fields. Subsea transport lines are used to transport the production fluid from the wellhead to a receiving platform. Unstable flow conditions can occur in subsea hydrocarbon production requiring artificial lift techniques to bring the hydrocarbons to the surface in new production, referred to as “green fields,” and/or during reservoir maintenance, referred to as “brown fields.” The hydrocarbon production fluids typically contain varying amounts of oil, gas, sediment, and water, resulting in variations of the multi-phase mixtures. These multi-phase mixtures can result in slug flow and other unstable flow conditions that can disrupt the transportation of the hydrocarbon production fluids to the surface. Slug flow commonly refers to a flowing production fluid in which large pockets of a gas are contained within a liquid.
Subsea separation units have been used to remove water and/or sediment from the production fluids to minimize slug flow. Gravity separators are used to combat slug flow in production fluids caused by water/oil mixtures by allowing the water in the production fluid to settle at the bottom of a vessel for separation thereof. Gravity separators, however, usually require a large vessel, which in a subsea environment can require excessive wall thicknesses resulting in a large, heavy vessel that can be difficult to position in subsea locations. Cyclone separators have been used to combat some of the size and weight limitations associated with gravity separators. Cyclone separators, however, typically require specific pressure differentials to achieve a desired degree of separation and such pressure differentials can be difficult to control in a subsea environment. Additionally, the use of gravity and cyclone separators are encumbered with additional costs due to the necessity of topside equipment.
There is a need, therefore, for new apparatus and methods for reducing slug flow from a multi-phase production fluid and/or separating hydrocarbons from the multi-phase production fluid.